Fractional Horsepower Electric Motor

  • Steel Frame construction through 400 HP; Cast Iron Frame construction through 350 HP; Aluminum Frame construction through 30 HP
  • Nameplated for 208V/60Hz and 50Hz Operation where applicable
  • Continuous Duty
  • Inverter-Rated insulation system – 1 HP and above and all Premium Efficient motors
  • NEMA Service Factors
  • UL Recognized Component Listing and CSA certified
For use where exposure to water, dust and corrosives exists. Ideally suited for use on pumps, compressors, blowers, fans, conveyors, machine tools and other direct or belt-driven applications. All 230/460V ratings nameplated for 208 Volt operation. Most 60Hz models nameplated for 50Hz.
  • Durable Rolled Steel Frame, Class B Insulation
  • High Quality Ball Bearings
  • Easy to Read Nameplate
  • Some 56 Frame Motors have a 56, 56H, 143T and 14ST Combination Base with 12 Mounting Holes for Flexible Installation.
  • UL Recognized Component Listing adn CSA Approval
Warranty 12 months from date of first use or 18 months from date of manufacture, whichever comes first.
  • Leesons Three-Phase AC Motors are Designed to Both EPACT and Premium Energy-Efficiency Mandates.
  • The AC Motors Meet the Energy Efficiency Requirements of the United States and Canada for General Purpose Industrial Motors.
  • Both ODP and Enclosed Designs In Frame Construction of Either Rolled Steel, Aluminum or Cast Iron and HP Ratings of1/6 HP Through 700 HP
Warranty 12 months from date of first use or 18 months from date of manufacture, whichever comes first.

Frequently Asked Questions

What types of motors are compatible with Gearboxes?
All types of motors are compatible with Gearboxes. For example: Stepper, Brushless, Brush, and AC motors are all compatible.

What types of motors are compatible with Gear Reducers?
Various types of motors are compatible with Gear Reducers. For example: Brushless, Brush, Stepper, and AC motors are all compatible.

How far away can I place my encoder from my system?
There is no set answer to this question. Many factors play a role in determining the maximum length of cable that can be used to connect the units together. The largest problem with running long lengths of cable is that the cable becomes more susceptible to noise. This is due to the capacitance of the cable, the cable acting as an antenna, and the loss of power through the cable. The maximum distance of cable can be achieved by following some basic wiring principles. Do not run the cable near objects that create a lot of electrical noise. this includes AC motors, arc welders, AC power lines, and transformers. Use twisted pair cabling when using the signal and its compliment, and shielded cabling when running any type of signal. Use the highest voltage available for the output voltage. For example, if the encoder will output 5 to 24 volts, then use 24 volts. Use an open collector or differential line driver output or differential receiver so that the maximum amount of current can be sink/sourced. If you are using the encoder as an input to more than one controller, use a signal amplifier. This is also a good way to help increase the distance for a differential line driver around 100ft., or more when using a differential input, and for an open collector the distance is around 35ft.

What is an AC Motor?
The standard definition ab AC Motor is an electric motor that is driven by an alternating current. The AC Motor is used in the conversion of electrical energy into mechanical energy. This mechanical energy is made from utilizing the force that is exerted by the rotating magnetic fields produced by the alternating current that flows through its coils. The AC Motor is made up of two major components: the stationary stator that is on the outside and has coils supplied with AC current, and the inside rotor that is attached to the output shaft.

What Types of AC Motors Exist?
AC Motors generally come in three different types. These types are known as: Synchronous, Industrial, and Induction AC Motors.

How do AC Motors work?
AC Motors fundamentally rely on the principles of magnetism. The simple AC Motor contains a coil of wire and two fixed magnets that surround a shaft. When an electric (AC) charge is applied to the coil, it becomes and electromagnet, generating a magnetic field. When the magnets interact, the shaft and the coil begin to rotate, this operates the motor.

In terms of construction, how do Permanent Magnet AC (PMAC) motors differ from AC Induction motors?
In the broadest sense, the major difference is in the rotor itself. In a squirrel cage induction motor, current is induced into the rotor from the field (stator) through the air gap, and conducted through aluminum (or other material) bars, which are most often die cast in the slots of the rotor laminations. In the case of a PMAC motor, the rotor itself contains permanent magnet material, which is either surface-mounted to the rotor lamination stack or embedded within the rotor laminations. In either topology, electrical power is supplied through the stator windings.

What are the primary benefits of PMAC motor versus AC Induction?
Permanent Magnet AC motors are inherently more efficient due to elimination of rotor conductor losses, lower resistance winding and “flatter” efficiency curve. Due to their synchronous operation, PMAC motors offer more precise speed control. PMAC motors provide higher power density due to the higher magnetic flux as compared with induction machines. Finally, Permanent Magnet motors generally operate cooler, resulting in longer bearing and insulation life.

What is a Two-Phase AC Induction Motor?
Most two-phase AC motors have a squirrel cage rotor and a field that hold two windings. The first a constant-voltage main winding and the second a control-voltage winding in quadrature. The second control-voltage winding creates a rotating magnetic field, which allows the motor to work in reverse.

What’s the difference between PMDC, PMAC, Brushless AC, PMSM (Permanent Magnet Synchronous Motor) and BLDC (Brushless DC)?
PMDC motors typically employ permanent magnets affixed to the inside of the motor frame, rotating wound armature and commutator (brushes). PMAC, PMSM and Brushless AC are synonymous terms. They are PM machines that operate on a PWM AC drive or control similar to an induction motor but with software to control a PM machine. BLDC motors are very similar to PMAC machines in terms of construction, but utilize DC (trapezoidal) drives rather than AC (“sine”) drives, which are used to control PMAC motors.

What is a VFD?
A VFD or Variable Frequency Drive, is a component that allows the speed of an AC motor to be changed. VFDs are able to vary the frequency and voltage applied to the motor and therefore, control the motor speed. VFDs also regulate the output voltage in proportion to the frequency to allow for a constant voltage to frequency (V/Hz) ratio.

What is Stearns known for?
Stearns is known for a lot of things but mainly for originating the AC Motor brake and inventing the DC Clutch and Brake in 1928.

What is the typical life expectancy of an AC Motor ?
Engineers are occasionally asked to predict average motor life or mean time between failures for a given three-phase induction motor. A reasonable answer can be obtained if the numerous variables that affect motor life are quantified, such as: 1. Supply voltage and frequency: Although NEMA MG1-12.44.1 stipulates that motors must tolerate +-10% voltage variation and +-5% frequency variation; the motor should be operated at nameplate voltage and frequency for optimum life. 2. Supply source: Supply voltage waveforms should be sinusoidal, balanced within 1%, per NEMA MG1-12.45, with rise times greater than 2 milliseconds and contain less than 2% total harmonic voltage distortion (typical of ‘clean’ utility power). This reduces turn-to-turn, coil-to-coil, and phase-to-ground voltage stress and prolongs motor insulation life. Hard-switching solid-state inverters must be equipped with output-side inductive filters with >5% impedance to provide a comparable waveform . 3. Motor environment: The motor must be installed in an environment that is appropriate for the motor enclosure. Ambient temperature should remain between (0 and 40)°C and elevation at 3300 ft or less. Motor ventilation must not be obstructed and mechanical shock and vibration must be held to a minimal level. 4. Bearing maintenance: Motor bearings must be properly lubricated per IOM published guidelines, with water and contaminants kept to a minimum. Bearing loads should be controlled to provide a minimum B-10 life of 25,000 hours and bearings must be replaced periodically to prevent permanent motor damage. Shaft voltages (caused by unbalanced line voltage or operation from inverter power) must be limited to 0.5 volts peak. 5. Motor Starting: Across-the-line starts should be kept to a minimum and not exceed NEMA MG1-12.54 guidelines, since the life of a motor is affected by the number of across-the-line starts. When the above conditions are met, the insulation life of the motor can be estimated with reasonable accuracy. In 1980 the US Department of Energy published report DOE / CS-0147 to define the average expected life of electric motors, which is summarized in the table below.

Does Motion Marketplace carry 56C Frame Motors ?
Motion Marketplace carries Leeson 56C Frame AC Motors in a single and three phase option for general purpose compressor duty AC motors.